Could PDF plot title number formatting be better?

Created by: wilsonmr

Opening here so somebody sees this

If you plot pdfs at 1.65 GeV the title will say 1.6, if you plot at 1.651 GeV it will say 1.7 GeV and the request is that it always plots the "actual" value: https://github.com/NNPDF/papers/issues/43#issuecomment-879263935

in practice I guess the formatting could be a bit better than just using float with 1 decimal place:

https://github.com/NNPDF/nnpdf/blob/74d91831393fff3335397037e498ea7bfd88e492/validphys2/src/validphys/pdfplots.py#L101

But I have a memory where it used to be general but there was a complaint that high scales we had scientific notation which was unacceptable.